JP6770195B2 - Method for producing unsaturated lower fatty acid ester - Google Patents

Description

The present invention relates to a method for producing an unsaturated lower fatty acid ester, and more particularly to a method for producing acrylic acid and methyl acrylate by subjecting methyl acetate and methylal to an aldol condensation reaction.

Acrylic acid and methyl acrylate are important chemical raw materials, can be used as paints, flocculants, dispersants, binders, etc., and are widely used in the fields of construction, water treatment, daily chemical products, soil treatment, leather, etc. , Has a close relationship with people's daily lives. Conventionally, the most commonly used method for producing acrylic acid and methyl acrylate in industry is the propylene two-stage oxidation method, that is, propylene is oxidized to acrolein in the first stage and oxidized in the second stage to produce acrylic acid. Is obtained. However, its raw material, propylene, is derived from petroleum, belongs to non-renewable resources, and does not fit the idea of sustainable development.

Lucite of the United Kingdom achieved the industrial production of methacrylic acid and its esters for the first time in 2010 by the aldol condensation reaction, and the annual production is 12,000 tons. In this method, methyl propionate is synthesized using raw materials such as ethylene, carbon monoxide and methanol in the first step, and the product is separated to obtain pure methyl propionate, and in the second step, methyl propionate and Methanol is introduced into a fixed bed reactor supported by a cerium oxide base catalyst, and then crudely separated and rectified to obtain methyl methacrylate. This method makes full use of the coal-based raw materials methanol and carbon monoxide, and is very consistent with the energy composition of Japan's coal-rich, petroleum-poor, and natural gas-poor, and our acrylic acid and its esters. It offers a novel route for industrialized manufacturing. Acetic acid and methyl acetate are important organic chemical raw materials and can be obtained by methanol carbonylation of coal-based raw materials. With the rapid development of C1 chemistry, the production capacity of acetic acid and methyl acetate has become excessive. Acrylic acid and methyl acrylate can be produced by subjecting formaldehyde to an aldol condensation reaction using inexpensive raw materials acetic acid and methyl acetate as raw materials, for the sustainable production of acrylic acid and methyl acrylate. Provides a viable method for.

In 1967, patent JP71016728B produced an acrylic acid or methacrylic acid product by subjecting acetic acid, propionic acid and formic acid to an aldol condensation reaction on a silica catalyst carrying an alkaline earth metal oxide. In 1966, James F. Vitcha (I & EC product research and development 1966, 5: 50-53) produced a Decalsos molecular sieve catalyst carrying an alkali metal, catalyzing the aldol condensation reaction of acetic acid and formaldehyde to acrylic acid and its esters. Where formaldehyde is provided by the aqueous formalin solution. Debraj Saha (Dalton Trans. 2014, 43: 1306-1307) produced Mg-MOF and Ca-MOF materials carrying two types of alkali metals in 2014, and catalyzed the aldol condensation reaction very well. Can exert. Mamoru Ai (Bull. Chem. Soc. Jpn. 1990, 63: 1217-1220; Bull. Chem. Soc. Jpn. 1990, 63: 3722-3724, etc.) produced a series of VPO composite catalysts. , These can effectively catalyze the aldol condensation reaction of propionic acid (ester) or acetic acid (ester) to produce lower unsaturated fatty acid esters.

The catalyst used for the aldol condensation reaction examined in the above literature is often a base catalyst or an acid-base bifunctional group catalyst, and in the manufacturing process thereof, the active ingredient is generally subjected to immersion, ion exchange, co-precipitation, or the like. It is carried on a carrier, is complicated to manufacture, has complicated influencing factors, has low reproducibility, and has drawbacks such as the active ingredient being easily washed away, and cannot satisfy the requirements for large-scale industrial production.

An object of the present invention is to provide a novel method for producing an unsaturated lower fatty acid ester.

The aldol condensation reaction can be carried out not only under a base catalyst, but also under acidic conditions as well. Industrially widely produced solid acid molecular sieves can be used as catalysts to avoid problems such as difficulty in separating products. Solid acid molecular sieves have advantages such as abundant pore structures, easy production, and a wide range of origins, and their use as catalysts for aldol condensation reactions is expected to have good industrial applications.

On this basis, the present invention is to aldol condensation reaction in methylal (DMM) and molecular formula R ₁ -CH ₂ -COO-R ₂ acid or ester and the reactor acidic molecular sieve catalyst is supported, the corresponding unsaturated Including obtaining a saturated lower fatty acid or ester, the R ₁ and R ₂ are independently H-, CH _3- , CH ₃ CH _2- , CH ₃ (CH ₂ ) _2- or CH ₃ (CH ₂ ) _{3, respectively.} Provided is a novel method for producing an unsaturated lower fatty acid ester which is a group such as −.

In one preferred embodiment, the unsaturated lower fatty acid or ester is further hydrogenated to produce the corresponding saturated alcohols.

In one preferred embodiment, the R ₁ and R ₂ are H- or CH _3- , respectively.

In one preferred embodiment, the methylal (DMM) and the lower saturated acid ester R _1- CH _2- COO-R ₂ are each brought into the reaction tube by a high pressure pump or a saturated gas and brought into contact with the acidic molecular sieve catalyst.

In one preferred embodiment, the acidic molecular sieve catalyst comprises any one of silica-alumina molecular sieves and aluminum phosphate molecular sieves, or a combination thereof. Preferably, the topological structure of the acidic molecular sieve catalyst includes any one of RHO, CHA, FER, MFI, MOR, FAU, βeta, or a combination thereof. More preferably, the acidic molecular sieve catalyst is any one of SAPO-34 molecular sieve, DNL-6 molecular sieve, ZSM-35 molecular sieve, ZSM-5 molecular sieve, MOR molecular sieve, Y molecular sieve, βeta molecular sieve and MCM-22 molecular sieve. Or include combinations thereof.

In one preferred embodiment, the silica-alumina molecular sieve atomic ratio of silica to alumina in the acidic molecular sieve catalyst is 1 to 50, preferably 2.5 to 25.

In one preferred embodiment, the acidic molecular sieve catalyst further comprises a product modified with an element other than the skeletal composition elements of the molecular sieve.

In one preferred embodiment, the acidic molecular sieve catalyst further comprises one or more metal elements selected from the group consisting of potassium, cesium , and copper. The metal element is introduced into the acidic molecular sieve catalyst by in-situ synthesis, metal ion exchange or immersion. The weight percentage of the metal element in terms of a single metal is 0.01 wt% to 10.0 wt% with respect to the total weight of the acidic molecular sieve catalyst.

In one preferred embodiment, the acidic molecular sieving catalyst comprises, as a binder, any one selected from the group consisting of alumina, silica, zirconia and magnesium oxide, or a combination thereof. The content of the binder is 0 wt% to 50 wt% with respect to the total weight of the acidic molecular sieve catalyst.

In one preferred embodiment, the molar ratio of methylal (DMM) to lower saturated acid ester in the raw material gas is 1/20 to 5/1, preferably 1/10 to 2/1.

In one preferred embodiment, the aldol condensation reaction is carried out at a temperature of 200-400 ° C. and a pressure of 0.2-15.0 MPa, preferably 250-350 ° C. and 0.2-5.0 MPa.

In one preferred embodiment, the total mass space velocity of the raw material is 0.05 to 10.0 h ^-1 , preferably 0.3 to 2.0 h ^-1 .

In one preferred embodiment, the aldol condensation reaction is carried out in a fixed bed reactor, a fluidized bed reactor or a tank reactor.

In one preferred embodiment, the aldol condensation _{reaction, N 2, He, Ar,} CH 4, C 2 H 6, H 2, CO, the atmosphere containing any one or a combination of CO ₂ It is done inside.

The present invention provides a novel method for producing an unsaturated lower fatty acid ester, particularly a novel method for producing acrylic acid and methyl acrylate, which is carried out on an acidic molecular sieve catalyst, has a high reaction activity, and is a catalyst. It is easy to industrialize and has features such as the catalytically active component not easily washed away, and is expected to have good industrial application.

In the present invention, an acid or ester having a molecular formula of R _1- CH _2- COO-R ₂ and methylal (DMM) are subjected to an aldol condensation reaction in a reactor carrying an acidic molecular sieve, and a corresponding unsaturated lower fatty acid or ester is subjected to the condensation reaction. (CH ₂ = C (R ₁ ) -COO-R ₂ ) is produced, and R ₁ and R ₂ are independently H-, CH _3- , CH ₃ CH _2- , CH ₃ (CH ₂ ) _2- or A method that is the basis of CH ₃ (CH ₂ ) ₃ -etc. Is provided.

In one particular embodiment, the present invention provides a method for producing acrylic acid and its esters by aldol condensation of methyl acetate and methylal on an acidic molecular sieve catalyst.

Preferably, the silica-alumina molecular sieve has an atomic ratio of 1 to 50, more preferably 2.5 to 25, in the acidic molecular sieve catalyst used in the present invention.

Preferably, the acidic molecular sieving catalyst further comprises one or more metal elements selected from the group consisting of potassium, cesium and copper. The metal element is introduced into the acidic molecular sieve catalyst by in situ synthesis, metal ion exchange, immersion or the like. Preferably, the weight percent of the metal element in terms of a single metal is 0.01 wt% to 10.0 wt% with respect to the total weight of the acidic molecular sieve catalyst.

Preferably, the acidic molecular sieving catalyst used in the present invention contains, as a binder, any one selected from the group consisting of alumina, silica, zirconia and magnesium oxide, or a combination thereof. Preferably, the content of the binder is 0 wt% to 50 wt% with respect to the total weight of the acidic molecular sieve catalyst.

Preferably, the lower fatty acid ester used in the present invention is methyl acetate, and acrylic acid and methyl acrylate can be obtained after the aldol condensation reaction.

Preferably, the aldol condensation reaction used in the present invention has a temperature of 200 to 400 ° C., a reaction pressure of 0.2 to 5.0 MPa, and a total mass space velocity of raw materials of 0.3 to 2.0 h- ^1. It is done in.

Preferably, the aldol condensation reactor used in the present invention is a fixed bed reactor, a fluidized bed reactor or a tank reactor.

Preferably, the aldol condensation reaction is carried out in an atmosphere containing any one of N ₂ , He, Ar, CH ₄ , C ₂ H ₆ , H ₂ , CO, CO ₂ or a combination thereof.

Further, although not particularly limited, in a suitable aldol condensation reaction, the molar ratio of methylal to methyl acetate is in the range of 1/10 to 2/1.

Examples Hereinafter, the present invention will be described in detail with reference to some examples, but the present invention is not limited to these examples.

Aluminum Phosphate Molecular Sieves DNL-6, SAPO-34 are reported by Dalian Institute of Chemical Physics in the literature using Microporous and Mesoporous Materials 144 (2011) 113-119 and Microporous and Mesoporous Materials 111 (2008) 143-149. It was produced and provided. The remaining molecular sieves and related raw materials were all obtained from the market.

The analysis method and conditions in the examples of the present invention are as follows.
Raw materials and products are detected online by Agilent 7890A gas chromatography using Agilent's FFAP capillary column.

According to one embodiment of the present invention, a fixed bed reactor is selected, the total mass space velocity of the raw materials is 0.3 to 2.0 h- ¹ , the reaction temperature is 200 to 400 ° C, and the reaction pressure. Is 0.2 to 5.0 MPa. The raw material is introduced into the reactor by the following method.

The temperature of the raw materials methyl acetate and methylal is maintained in a water bath (20 ° C.), nitrogen gas N ₂ is introduced and bubbling is performed, and saturated steam containing the raw materials enters the fixed bed reactor and of nitrogen gas. The amount of raw material entering the reactor can be adjusted based on the flow velocity. Under different temperature conditions, the saturated vapor pressure of the raw material can be calculated by the following formula.
lg P ^* = AB / (t + C)
In the formula, A, B, and C represent different physical property parameters of raw materials, and t represents temperature, as can be seen by inquiring Lange's Handbook of Chemistry. In this way, the saturated vapor pressure of the raw material under an arbitrary temperature can be calculated. From the saturated vapor pressure, the amount of raw material entering the reactor per unit time can be calculated.
Conversion rate of methylal = [(number of moles of methylal in the charged sample)-(number of moles of methylal in the discharged sample)] / (number of moles of methylal in the charged sample) x (100%)
Methyl acetate conversion rate = [(number of moles of methyl acetate in the charged sample)-(number of moles of methyl acetate in the discharged sample)] / (number of moles of methyl acetate in the charged sample) x (100%)
Selectivity of acrylic acid and methyl acrylate = (number of moles of carbon atoms of acrylic acid and methyl acrylate in the discharged sample) / (total number of moles of carbon atoms of all products-number of moles of carbon atoms of dimethyl ether) × (100%) )

In the examples of the present invention, the product contains a large amount of dimethyl ether, which can be industrially circulated to replenish the raw material, so that the dimethyl ether product is not taken into account when calculating the selectivity.

1 Example of catalyst production 1.1 Aluminum phosphate molecular sieves SAPO-34 and DNL-6 were produced by Dalian Institute of Chemical Physics using the hydrothermal method. The raw powder was calcined at 550 ° C. for 4 hours, and pressure was applied to obtain 20-40 mesh 1 # and 2 # catalysts, respectively.

1.2 Silica-alumina molecular sieves 100 grams of Na-Y, Na-MOR, βeta and Na-ZSM-5 molecular sieves with calcined silica-alumina ratios of 2.5, 6.5, 20, and 21.5, respectively. Exchange 3 times with 5 Mol / L ammonium nitrate aqueous solution, wash with deionized water for 2 hours each time, dry and bake at 550 ° C. for 4 hours, hydrogen type Y molecular sieve, hydrogen type MOR molecular sieve. , Hydrogen-type βeta molecular sieves and hydrogen-type ZSM-5 molecular sieves were obtained, and 20 to 40 meshes of 3 #, 4 #, 5 # and 6 # catalysts were obtained by pressing.

1.3 Molding of hydrogen type MOR silica-alumina molecular sieve 80 g of Na-MOR molecular sieve having a silica-alumina ratio of 6.5 and 28 g of pseudo-bemite are uniformly mixed with 10% dilute nitrate, then extruded and baked at 550 ° C. for 4 hours. Then, it was replaced with 0.5 mol / L ammonium nitrate three times, each time for 2 hours, washed with deionized water, dried, and baked at 550 ° C. for 4 hours to obtain a catalyst 7 #. ..

80 g of Na-MOR molecular sieve having a silica-alumina ratio of 6.5 and 20 g of pseudo-boemite are uniformly mixed with 10% dilute nitric acid, extruded, calcined at 550 ° C. for 4 hours, and 3 with 0.5 mol / L ammonium nitrate. It was exchanged once for 2 hours each time, washed with deionized water, dried, and calcined at 550 ° C. for 4 hours to obtain catalyst 8 #.

80 g of Na-MOR molecular sieve having a silica-alumina ratio of 6.5 and 50 g of pseudoboemite are uniformly mixed with 10% dilute nitric acid, extruded, calcined at 550 ° C. for 4 hours, and 3 with 0.5 mol / L ammonium nitrate. It was exchanged once for 2 hours each time, washed with deionized water, dried, and calcined at 550 ° C. for 4 hours to obtain catalyst 9 #.

1.4 Supported M / ZSM-5 catalyst A supported M / ZSM-5 catalyst is produced by an equal volume immersion method. 2.02 g of KNO ₃ , 3.24 g of Cs ₂ CO ₃ and 1.88 g of Cu (NO ₃ ) ₂ were each dissolved in 18 ml of deionized water to prepare a corresponding aqueous nitrate solution. 20 g of each 6 # catalyst was added to the above salt solution, allowed to stand for 24 hours, then separated and washed with deionized water, and the obtained sample was dried in an oven at 120 ° C. for 12 hours and dried. The latter sample was left in a muffle furnace, heated to a treatment temperature of 550 ° C. at a heating rate of 2 ° C./min, and baked for 4 hours to obtain catalysts of 10 #, 11 #, and 12 #, respectively.

2 Synthesis Example 2.1 Aldol Condensation Reaction on Different Molecular Sieves 1 # to 12 # acidic molecular sieves having different topology structures were locked at a pressure of 40 MPa, and particles of 20 to 40 mesh were selected and measured. .. The molecular sieve catalyst is filled in a fixed bed reactor and the catalyst is preactivated, the conditions being that the flow rate of N ₂ is 30 ml / min, the temperature is raised to 500 ° C. at a rate of 2 ° C./min, and further. The temperature was maintained at 500 ° C. for 1 hour, then the temperature was lowered to a desired reaction temperature of 350 ° C. under a nitrogen gas atmosphere, the pressure of the reaction system was raised to 3 MPa using nitrogen gas, and the molar ratio of methylal to methyl acetate was 2. Table 1 shows the results of the Aldor condensation reaction under these conditions, which is 1/1 and the total mass space velocity of the raw materials is 0.3 h ^-1 .

2.2 Results of aldol condensation reaction at different reaction temperatures 0.5 g of 6 # catalyst was filled in a fixed bed reactor with an inner diameter of 8 mm, and 500 at a heating rate of 2 ° C./min under a nitrogen gas atmosphere. The temperature was raised to ° C. and held for 1 hour, then lowered to a desired reaction temperature under a nitrogen gas atmosphere, and the pressure of the reaction system was further raised to 3 MPa using nitrogen gas. The reaction raw materials were introduced into the reactor from top to bottom, the molar ratio of methylal to methyl acetate was 2/1, the total mass space velocity of the raw materials was 0.3 h ^-1 , and under different reaction temperatures. The results of the aldol condensation reaction are shown in Table 2.

2.3 Results of aldol condensation reaction under different reaction pressures 0.5 g of catalyst of 6 # was filled in a fixed bed reactor with an inner diameter of 8 mm, and the temperature was raised at 2 ° C./min in a nitrogen gas atmosphere. The temperature was raised to 500 ° C. and held for 1 hour, then lowered to 350 ° C. under a nitrogen gas atmosphere, and the pressure of the reaction system was further raised to the pressure required for the reaction using nitrogen gas. The reaction raw materials were introduced into the reactor from top to bottom, the molar ratio of methylal to methyl acetate was 2/1, the total mass space velocity of the raw materials was 0.3 h ^-1 , and under different reaction pressures. The results of the aldol condensation reaction are shown in Table 3.

2.4 Results of aldol condensation reaction with different methylar to methyl acetate molar ratios 0.5 g of 6 # catalyst was introduced into a fixed bed reactor with an inner diameter of 8 mm and at 2 ° C./min under a nitrogen gas atmosphere. The temperature was raised to 500 ° C. at a heating rate, held for 1 hour, then lowered to 350 ° C. under a nitrogen gas atmosphere, and the pressure of the reaction system was further raised to the pressure required for the reaction of 3 MPa using nitrogen gas. .. The reaction raw materials were introduced into the reactor from top to bottom, the total mass space velocity of the raw materials was 0.3 h ^-1 , and the molar ratio of methylal to methyl acetate was 2/1, 1/1, 1/10. The results of the aldol condensation reaction are shown in Table 4.

2.5 Results of aldol condensation reaction between methylal and different fatty acid esters on acidic molecular sieves

0.5 g of the catalyst of 6 # was filled in a fixed bed reactor having an inner diameter of 8 mm, heated to 500 ° C. at a heating rate of 2 ° C./min under a nitrogen gas atmosphere, held for 1 hour, and then held. The temperature was lowered to 350 ° C. under a nitrogen gas atmosphere, and the pressure of the reaction system was further increased to the pressure required for the reaction of 3 MPa using nitrogen gas. The reaction raw materials were introduced into the reactor from top to bottom, the total mass space velocity of the raw materials was 0.3 h- ¹ , the molar ratio of methylal to different fatty acid ester raw materials was 2/1, and the aldol condensation thereof. The results of the reaction are shown in Table 5.

2.6 Results of aldol condensation reaction under different raw material mass space velocities Using 6 # catalyst, reaction temperature is 350 ° C., total mass space velocities of raw materials are 0.3h ^-1 , 1.0h ^-1 , 2. It is 0h ^-1 , and other conditions are the same as in Example 2.1, and the reaction results are shown in Table 6.

2.7 Reaction results of different reactor types Using the catalyst of 7 #, the reaction temperature is 350 ° C., the reactors are a fluidized bed reactor and a moving bed reactor, respectively, and other conditions are the same as in Example 2.1. Is. The reaction results are shown in Table 7.

2.8 Reaction results under different reaction atmospheres Using a catalyst of 10 #, the reaction temperature was 350 ° C., the reaction atmospheres were N ₂ , H ₂ , He, and CO, respectively, and other conditions were the same as in Example 2.1. The same is true. The reaction results are shown in Table 8.

Although the present invention has been described in detail above, the present invention is not limited to the specific embodiments described in this specification. It should be understood that one of ordinary skill in the art may make other modifications and modifications without departing from the scope of the present invention. The scope of the present invention is limited by the appended claims.

Claims (15)

Methylal and molecular formula was aldol condensation reaction of an ester of R ₁ -CH ₂ COOR ₂ in an acidic molecular sieve catalyst in a reactor carried include obtaining a corresponding unsaturated lower fatty acid or ester,
The R ₁ is selected from H −, CH ₃ −, CH ₃ CH ₂ −, CH ₃ (CH ₂ ) ₂ − and CH ₃ (CH ₂ ) ₃ − .
The R ₂ is selected from CH ₃ −, CH ₃ CH ₂ −, CH ₃ (CH ₂ ) ₂ − and CH ₃ (CH ₂ ) ₃ −.
The acidic molecular sieve catalyst includes one or more selected from the group consisting of silica-alumina molecular sieves, aluminum phosphate molecular sieves and combinations thereof.
The silica-alumina molecular sieves include one or more selected from the group consisting of ZSM-35 molecular sieves, ZSM-5 molecular sieves, MOR molecular sieves, Y molecular sieves, βeta molecular sieves, MCM-22 molecular sieves and combinations thereof.
The aluminum phosphate molecular sieves include one or more selected from the group consisting of SAPO-34 molecular sieves, DNL-6 molecular sieves, and combinations thereof .
A method for producing unsaturated lower fatty acids or esters. The method of claim 1, wherein the acidic molecular sieve catalyst comprises a ZSM-5 molecular sieve. The method of claim 1, wherein R ₁ is selected from H- and CH _3- and R ₂ is selected from CH _3- . The atomic ratio of silica to alumina of silica-alumina molecular sieves under acidic molecular sieve catalyst is 1 to 50, The method of claim 1. The method according to claim 4 , wherein the silica-alumina molecular sieve has an atomic ratio of 2 to 25 of silica in the acidic molecular sieve catalyst. The method according to claim 1 , wherein the acidic molecular sieve catalyst further contains a product modified with an element other than the skeletal composition element of the molecular sieve. The method according to claim 6 , wherein the acidic molecular sieving catalyst further contains one or more metal elements selected from the group consisting of potassium, cesium , and copper. The method according to claim 7 , wherein the metal element is introduced into the acidic molecular sieve catalyst by in situ synthesis, metal ion exchange or immersion. The method according to claim 8 , wherein the weight percentage of the metal element in terms of a single metal is 0.01 wt% to 10.0 wt% with respect to the total weight of the acidic molecular sieve catalyst. The method according to any one of claims 1 to 9 , wherein the acidic molecular sieve catalyst comprises any one selected from the group consisting of alumina, silica, zirconia and magnesium oxide or a combination thereof as a binder. The method according to claim 10 , wherein the content of the binder is more than 0 wt% and 50 wt% or less with respect to the total weight of the acidic molecular sieve catalyst. The molar ratio of methylal to the acid or ester is 1 / 20-5 / 1, the total mass space velocity of the raw materials is 0.05 to 10.0 h- ¹ , the reaction temperature is 200 to 400 ° C, and The method according to claim 1, wherein the reaction pressure is 0.2 to 15.0 MPa. The molar ratio of methylal to the acid or ester is 1/10 to 2/1, the total mass space velocity of the raw materials is 0.3 to 2.0 h- ¹ , the reaction temperature is 250 to 350 ° C, and The method according to claim 12 , wherein the reaction pressure is 0.2 to 5.0 MPa. The method according to claim 1, wherein the aldol condensation reaction is carried out in a fixed bed reactor, a fluidized bed reactor or a tank reactor. The aldol condensation reaction is carried out in an atmosphere containing any one selected from N ₂ , He, Ar, CH ₄ , C ₂ H ₆ , H ₂ , CO, and CO ₂ or a combination thereof. The method according to claim 1.